Draku, Sydney Emmanuel2026-01-282026-01-282025-10-14Draku, S. E. (2025). Assessment of microplastics in selected rivers, fish, and wastewater from car wash bays in Arua city (Unpublished graduate dissertation). Muni University, Arua, Ugandahttps://dir.muni.ac.ug/handle/20.500.12260/905A research dissertation submitted to the department of chemistry, faculty of science, in partial fulfillment of the requirements leading to the award of the degree of master of science in chemistry of Muni UniversityMicroplastics (MPs) are increasingly recognised as critical pollutants in freshwater ecosystems, yet data from sub-Saharan urban settings remain limited. This study investigated the occurrence, distribution, and polymer composition of MPs in car wash effluents, receiving river water, and fish in Arua City, Uganda. Five (5) car wash bays and two rivers (Asa and Enyau) were purposively selected. Ten (10) litres of river water, one (1) litre of wastewater, and twenty (20) fish samples were collected and processed via filtration (300–0.45 μm), oxidative digestion, and polymer identification using micro– Fourier Transform Infrared Spectroscopy (μFTIR). One-way ANOVA results revealed significantly higher MP concentrations in bays employing jet washing and exhibiting prolonged wastewater retention (F = 133.98, p < 0.05). Fibres and fragments comprised >80% of particles, with dominant polymers being polyethylene (PE), polypropylene (PP), and ethylene-based copolymer (EPC). Mean MP levels in both rivers were observed to be in the same range, with spatial heterogeneity linked to local anthropogenic activity. Fish from River Asa showed the highest MP loads, positively correlated with body length (r = 0.714, p = 0.000). Findings position car wash facilities as major sources of microplastics, calling for targeted regulatory and infrastructural interventions, alongside public awareness campaigns and further research to mitigate microplastic pollution in Arua City.enMicroplasticsRiversfishand wastewaterCar wash baysArua city